Bay and Catchments

Report Card for July 2015 – June 2016

This Report Card provides a snapshot of water quality in Port Phillip Bay and catchments from 1 July 2015 to 30 June 2016. The quality of the water is given an overall score by combining the results of a number of standard water quality parameters: nutrients, water clarity, dissolved oxygen, salinity, pH, metals and algae.

Over the 2015–16 year, water quality in the river systems and the Bay has marginally declined, except in the Yarra and Mornington catchments where conditions were either maintained or showed improvement.

Summary Table: The table below shows the percentage of the Bay and surrounding catchments that fall into each scoring category. See the scoring method for more information.

Area

Score

9%

Very Good
Near-natural high quality waterways

Forested upper catchments and entrance to Port Phillip Bay

26%

Good
Meets Victorian water quality standards

Upper catchments and Port Phillip Bay

25%

Fair
Some evidence of stress

Mostly the main rivers and tributaries in the middle catchment areas on the urban fringe

12%

Poor
Under considerable stress

Mostly lower reaches of the main rivers and urban tributaries

28%

Very Poor
Under severe stress

Mostly small urban tributaries

In 2015–16, routine monitoring occurred across 101 sites in the Bay and catchments. This represents 80 per cent of the total catchment area. The remaining 20 per cent of the catchments not monitored are mostly rural and would typically score as ‘Fair’.

The section Changes over time compares the 2015–16 Report Card scores and indicators for the catchments and the Bay to previous Report Cards (since 2000). More detail on the specific catchments and the Bay is provided in their individual reports.

Site-specific details within the Bay and each catchment can also be accessed directly from the map or within the individual catchment and Bay reports.

How did rainfall impact on water quality?

Changes in rainfall can have a big impact on water quality. In 2015–16, rainfall across the region was below the historic average. During winter and spring of 2015, rainfall was approximately 11 per cent and 49 per cent below the average. During summer and autumn of 2016 rainfall was approximately 19 per cent and eight per cent below the average (Bureau of Meteorology, 2016).

These drier conditions led to significantly reduced river flow. In some cases, this resulted in no water at all, reducing some waterways to isolated pools or dry river beds, particularly in small tributaries. This generally means either there’s no water to sample or that there is a drop in water quality for some parameters. Reduced flow often results in low oxygen levels, increased salinity and algal blooms, all of which can cause stress to aquatic life. For the Werribee and Maribyrnong catchments in their ‘natural’ state these waterways would likely dry out entirely during summer, leaving remnant chains of ponds where ground water meets the surface.

Dry conditions can also result in less stormwater runoff, leading to lower turbidity and nutrient levels in streams. A decrease in these parameters will appear as improvements to the condition of waterways.

Events

The Report Card's water quality index is based on routine sampling which means the short-lived environmental and weather events that can impact water quality are not always captured. The following events occurred during the 2015–16 reporting period:

During November 2015, a storm brought heavy rain and flash flooding to parts of the Melbourne metropolitan region. Other significant rainfalls occurred in July, August and December 2015; and January, March and April 2016. All of these events had the potential to impact waterways with stormwater runoff from the hard surfaces in the city.

Environmental flow releases (controlled releases of water) occurred in the Werribee, Maribyrnong and Yarra catchments. Key objectives of environmental water releases are to improve water quality; flush out sediment to improve habitat; and to stimulate breeding of fish by providing high water flows at the right time of the year.

An algal bloom occurred at Williamstown Beach in December 2015. The bloom only lasted one day and dissipated naturally. In January a blue-green algae bloom developed in the Werribee River, downstream of the Maltby Bypass and persisted for several weeks before finally dissipating after an additional environmental water release in early March. Blue-green algae occurs naturally in waterways, typically in summer, and can erupt into blooms during hot weather, periods of low flows, or where there is an accumulation of nutrients.

In November 2015 Merri Creek was impacted by a large fire in Somerton when water from fire-fighting efforts drained into Merri Creek, carrying pollutants and reducing the dissolved oxygen level in the creek. Water was extracted from drains and the creek where possible and aerating pumps were installed at key locations in Merri Creek in an effort to improve conditions.

In November 2015, a second fire in Broadmeadows at a recycled tyre factory impacted Merlynstons and Campbellfield Creeks. Run-off from this fire was largely diverted from nearby drains to the sewer, so impacts to the creek were successfully minimised.

Underwater near Rye Pier. Source: EPA Victoria

Volunteers cleaning up a shoreline. Source: Melbourne Water

Changes over time

The Bureau of Meteorology has identified a long-term ‘drying’ trend since the 1970s in the Melbourne metropolitan region, which shows that annual rainfall is decreasing by 50 mm every 10 years. This is one of the most significant rainfall declines across the state of Victoria.

Since 2000, there has been an overall improvement in water quality in most of the larger catchments and the Bay. In some catchments this may be partially attributed to changes in the monitoring program.

During times of low rainfall, the condition of some streams’ water quality may improve as there is little to no input from urban and rural runoff. This results in lower levels of nutrients and pollutants, and improved water clarity. However, low rainfall for some streams can reduce flows to the point where dissolved oxygen declines to levels that impact the aquatic life in the rivers. In some streams, particularly those in the north-west, salinity naturally increases during times of low rainfall because flow is more dominated by salty groundwater springs.

During times of high rainfall streams are impacted more by increased runoff, which decreases water clarity and increases nutrients and pollutants that enter waterways. The drought breaking rains in 2010 and the well above-average rainfall in 2011 resulted in declines in water quality.

Average conditions over the next three years resulted in improvements in water quality up to 2013–14. However, low rainfall conditions continued over the last two years, resulting in the general drying of the river catchments. Several rivers and creeks were reduced to isolated pools or dried completely. It is expected the return of water to these streams will result in improved water quality. Over the 2015–16 year, water quality in the river systems and the Bay has marginally declined, except in the Yarra and Mornington catchments where conditions were either maintained or showed improvement.

While climate has shaped much of the water quality condition for the region over this period, the Dandenong and Mornington catchments have consistently shown ‘Poor’ to ‘Very Poor’ water quality. In these catchments, waterways tend to be small or highly modified from their natural state. Their size makes them more susceptible to the impacts of urban and industrial land use and the pollution that these types of land uses bring.

Plot of water quality index (WQI) score history for all catchments and the Bay.

Actions

What's happened?

The Government, authorities and community have implemented the following initiatives to improve waterway health in the Bay and catchments:

Melbourne Water in 2015–16:

removed over 3340m3 of debris, including litter and 5,000m3 of silt from waterways and litter traps

planted almost 120km of streamside vegetation across the region

controlled weeds along 1500 km of waterway

funded the installation of 61 km of fencing to exclude stock from entering waterways

removed two fish barriers to improve fish passage

funded 45 council Integrated Water Management projects totalling $3 million through the Living Rivers Grants

The Department of Environment, Land, Water and Planning (DELWP) initiated the revision of the Port Phillip Bay Environmental Management Plan. This plan, to be finalised in 2017, outlines a vision, objectives and actions to maintain the health and amenity of the Bay into the future. The Plan also identifies key threats and sets targets to protect the Bay. The Plan will help Government and other organisations work together to address the key challenges of managing Port Phillip Bay.

The Victorian Government has prioritised the protection and improvement of Victoria's water environments. To ensure Victoria has clear and relevant standards, legal rules and statutory obligations to protect and improve the health of our water environments, the Government is reviewing two key policies State Environment Protection Policies (SEPPs): – SEPP Waters of Victoria and SEPP Groundwaters of Victoria.

EPA's summer litter campaign A cleaner Victoria is in your hands, which encourages people to report litter thrown from vehicles via EPA's online reporting tool or mobile apps. It is specifically aimed at creating awareness about the impact of litter on our natural assets such as the Bay and its catchments.

The $2 million 2014-2017 Litter Hotspots grants program was introduced by EPA in 2014. This program is led by the Melbourne Waste and Resource Recovery Group, working with local councils and community groups to find local litter solutions.

Improved communication of water quality to the community through the Yarra & Bay website.

The Waterways Ecosystem Research Group at the University of Melbourne, is a group of researchers studying interactions between landscapes and running waters. The group is involved in the development and application of hydrologic, hydraulic and ecological models for achieving healthy streams and rivers in urban and rural landscapes.

The Centre for Aquatic Pollution, Identification and Management (CAPIM) is a scientific research organisation, established to identify and address the impact of pollution in water environments. CAPIM's goal is to improve aquatic ecosystem health by developing innovative approaches to pollution detection for inland waters and estuaries, and working with environmental management practitioners to reduce pollution impacts.

For more information on initiatives that are improving waterways in the Port Phillip Bay and catchments in 2015–16, please visit Waterways Local Updates.

What's planned?

A number of priority areas and actions have been identified for the Bay and catchments that will build on existing projects and initiatives. Priority management actions include:

Melbourne Water's Healthy Waterways Strategy, which outlines Melbourne Water's role in managing rivers, estuaries and wetlands in the Port Phillip and Western Port region, and identifies actions planned for the future to preserve and protect waterways.

Roll out of the $2 million 2014–2017 Litter Hotspots grants program. The Litter Innovation Fund, announced in December 2015, provides support for the Victorian community, including government, business, not-for-profit organisations, social enterprises and schools, to fund innovative approaches that prevent and reduce the impact of litter and illegal dumping. A proportion of the Fund has been specifically allocated to support projects that help reduce litter and illegal dumping in the Yarra River and Port Phillip Bay catchment.